Houston Police launched a homicide investigation into the deaths of four individuals after firefighters discovered their remains inside a burning vehicle.

In an interview with Click2Houston, Harris County Sheriff’s spokesman Tom Gilliland said firefighters responded to the blaze in Channelview and found the charred bodies of two people, one male and a female in the trunk of a KIA sedan on Friday morning.

After calling authorities, investigators found the remains of two more individuals, a male, and female in the back seat of the burning car.

Police officials believe the car was set on fire to cover up the murder of the four people.